I did it like this for all the coins I'm following. I use separate internal hdd like F:, just for blockchains.

1.) exit from wallet, check task manager - details, that process is no running

2.) Copy all XX gb of files from:

• "C:\Users\Donald\AppData\Roaming\croat"
  to
  "F:\croat"

and wait for it to copy everything.

* you can copy the complete folder also, or by drag'n'drop or copy/paste folder

3.) Delete

• "C:\Users\Donald\AppData\Roaming\croat" (folder)

* basically steps 2 and 3 are moving, but this is safer way - copy/delete - because of many files/big files

4.) Open Administrator command prompt and then:

• MKLINK /J "C:\Users\Donald\AppData\Roaming\croat" "F:\croat"

* before this command, folder "C:\Users\Donald\AppData\Roaming\croat" doesn't exist (it's deleted in step 3.)

5.) Nothing to change in CroatCore.
On old location (C:\Users\Donald\AppData\Roaming\croat), you will now have symbolic link to the files actually residing on other hdd.